Most Americans grew up thinking of tacos as those crunchy, sunny yellow circles folded into a deep-sided boat just wide enough to hold a spoonful of timidly spicy filling and narrow enough to contain our ideas of what Mexican cooking is.

Our Mexican friends and neighbors had a different definition: Two tortillas, much paler but also much tastier, folded around grilled or stewed meat, onions, cilantro, maybe salsa. Or pineapple, if it's pork, maybe cucumbers.

But it took awhile to realize that a taco is as versatile as a sandwich. Kogi BBQ in Los Angeles started serving tacos with Korean barbecue tucked inside, and the definition of a taco changed forever.

At Taco Fest in Cincinnati this weekend, all kinds of tacos will be for sale. Bakersfield will bring their popular two-tortilla tacos. There will be traditional examples from Molca Salsa Taco, including lengua and trippa (that's tongue and tripe). But there will be many far less conventional tacos as well. Head out and expand your taco horizons.